Mortgage Savings Calculator

Calculate how much you save with four proven mortgage payoff strategies — individually and combined. See rankings, effort vs. reward analysis, and whether investing beats paying down your mortgage.

$
%
years
Total Interest Over 30 Years
$467,234
Base payment: $2,270/mo — savings from 4 strategies below
Extra $100/mo
Save $66,868
(3.6 yrs early)
Biweekly Payments
Save $110,411
(6.0 yrs early)
15yr Instead of 30yr
Save $259,741
(+$827/mo)
Rate 0.5% Lower
Save $41,430
(−$115/mo)

Combine strategies for compounding savings — but note they are NOT simply additive. The calculator compounds them correctly.

$
%
Combined Interest Cost
$267,364
Total Savings
$199,870
Payoff In
20yr 3mo
Years Saved
9.8 years

What if instead of making extra mortgage payments, you invested $100/month at market returns? Compare the wealth outcomes.

%
Interest Saved (extra $100/mo)
$66,868
guaranteed return = your rate
Investment Value of $100/mo
$108,269
at 8.0% over 317 months
Net Difference
$41,401
Investing wins
Breakeven Investment Return
6.75%
to match mortgage paydown
Paying down your mortgage is a guaranteed 6.75% after-tax return. Investing at 8.0% is higher but not guaranteed. The right choice depends on your risk tolerance and tax situation.

How to Use This Mortgage Savings Calculator

Enter your Loan Amount, Interest Rate, and Loan Term. The Quick calculator instantly shows how much you save with four strategies: making an extra $100/month, switching to biweekly payments, choosing a 15-year term instead of 30, or securing a rate 0.5% lower.

Use Advanced to combine multiple strategies at once (with accurate compound calculation — not just adding individual savings), see a ranked table for your specific loan, and view the effort vs. reward matrix. Use Pro to model what happens if you invest your savings instead, how extra payments affect your tax deduction, and get a personalized allocation recommendation.

Four Ways to Save on Mortgage Interest

Total Interest = Monthly Payment × Months − Loan Amount

Extra Payment Savings = Base Total Interest − Accelerated Total Interest

Biweekly Effect: 26 half-payments/yr = 13 full payments (vs 12 standard)
Extra principal per year ≈ 1 monthly payment

15yr vs 30yr: Same rate, same loan — 15yr pays off in half the time
On $350K at 6.75%: 30yr interest = $477K, 15yr interest = $207K
Savings = $270K (but monthly payment is $1,100 higher)

Mortgage Savings Comparison — $350,000 Loan at 6.75%

Four Strategies Side by Side

StrategyInterest SavedYears SavedMonthly Cost
Extra $100/month~$46,0005.2 years+$100
Biweekly payments~$56,0004.5 yearsSame (timing change)
15yr instead of 30yr~$270,00015 years+$1,100
Rate 0.5% lower~$38,0000 years−$120 (saves money)

Note: combining strategies saves more than the sum of parts — each dollar of principal paid early eliminates all future interest on that dollar, compounding the effect.

Biweekly Payments Explained

Biweekly payments are the single lowest-effort, highest-impact mortgage savings strategy. Instead of 12 monthly payments per year, you make 26 half-payments — equivalent to 13 full months. That extra month of principal reduces your loan faster with zero budget increase.

Ask your servicer to set up true biweekly payments (where the extra is applied to principal immediately). Some servicers hold the second half-payment until month-end — defeating the purpose. Alternatively, simply divide your monthly payment by 12 and add that amount to each regular payment.

Frequently Asked Questions

On a $350,000 loan at 6.75%, biweekly payments save approximately $56,000 in total interest and cut the loan from 30 years to 25.5 years. By making half your payment every two weeks, you make 26 half-payments per year — equivalent to 13 monthly payments instead of 12. That extra month annually removes years of interest over the life of the loan.
The math depends on your mortgage rate vs. what you can earn investing. At 6.75%, paying down your mortgage guarantees a 6.75% return. If you can earn more after tax by investing (historically possible with broad stock index funds), investing may win. But mortgage paydown is risk-free. Recommended order: (1) Emergency fund, (2) 401K match, (3) then compare your rate to expected investment returns.
Yes, and they compound. Combining biweekly payments + $200 extra/month + a rate reduction can save over $100,000 on a 30-year loan. The savings are NOT simply additive — each extra dollar of principal paid early eliminates all future interest on that dollar, so the combined effect is greater than the sum of individual strategies.
Yes, but usually minimally. If you save $50,000 in interest through extra payments, you lose the deduction on that $50,000. At the 24% bracket, that's $12,000 less in deductions — reducing your net savings to $38,000. However, since the standard deduction was raised to $29,200 (married filing jointly, 2024), fewer than 14% of taxpayers now itemize, meaning most homeowners won't be affected by this at all.
Biweekly payments are free — they require no extra budget, just a timing change. Ask your servicer to switch to true biweekly billing (not just holding payments). If you have $50–$100 extra, add it as a principal payment each month. Small amounts matter more in early years when your balance is highest and more payment goes to interest.

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